Abstract: The present invention relates to an indexing tab for use with a sorting device including a plurality of sheet, or plate-like, divider leaves. The tab is secured to the free end of a divider leaf and includes a central body portion having a thickness greater than the thickness of the leaf and thinner elongate end portions which project outwardly from opposite ends of the body portion. The thick body portion maintains a spaced relation between the free ends of the divider leaves for inserting sheet material therebetween, and the thinner end portions provide guideway spaces into which an edge margin of a sheet may be slipped to insert a sheet between the divider leaves. Beveled exterior surfaces on the tab permit ease of insertion and removal of sheets in the device.